| (19) |
 |
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(11) |
EP 0 267 597 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
08.03.1989 Bulletin 1989/10 |
| (43) |
Date of publication A2: |
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18.05.1988 Bulletin 1988/20 |
| (22) |
Date of filing: 11.11.1987 |
|
| (51) |
International Patent Classification (IPC)4: C02F 5/14 |
|
| (84) |
Designated Contracting States: |
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AT BE CH DE ES FR GB GR IT LI LU NL SE |
| (30) |
Priority: |
13.11.1986 US 929971
|
| (71) |
Applicant: THE B.F. GOODRICH COMPANY |
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Akron
Ohio 44313-1799 (US) |
|
| (72) |
Inventors: |
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- Amjad, Zahid
Avon Lake
Ohio 44012 (US)
- Masler, William Frank, III
Hinckley
Ohio 44233 (US)
|
| (74) |
Representative: von Kreisler, Alek, Dipl.-Chem. et al |
|
Patentanwälte
von Kreisler-Selting-Werner
Postfach 10 22 41
50462 Köln
50462 Köln (DE) |
|
| |
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| (54) |
Calcium phosphonate scale inhibition |
(57) Addition of a secondary scale inhibitor is made to a water medium containing a primary
phosphonate scale inhibitor to inhibit precipitation of insoluble calcium phosphonates
which are formed by the reaction of calcium in the water medium with the primary scale
inhibitor thus forming insoluble calcium phosphonate. The secondary scale inhibitor
has the function of inhibiting precipitation of such insoluble calcium phosphonates.
The secondary scale inhibitor is a copolymer of an acrylic acid and/or methacrylic
acid with one or more of a principal comonomer selected from substituted acrylamides,
alkoxyalkyl acrylates, substituted and unsubstituted alkyl acrylates, acrylamido alkane
sulfonic acids, hydroxyalkyl acrylates, alkyl itaconates, and mixtures thereof.